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Generally, metals are easy to wear, so material modification is needed to increase hardness to increase the material's resistance to wear and tear. One way is to do a hard chrome plating process using the electroplating method and then continue the heat treatment process. This research was conducted to observe changes in the mechanical properties and microstructure of S45C steel that underwent hard chrome and heat treatment processes. This research was conducted by inserting S45C steel as a cathode into hard chrome liquid and using lead (Pb) as the anode. A positive (+) current powers the anode, the cathode has a negative current (-), the voltage used is 12 V with a duration of 60 minutes. After the cathode was coated with hard chrome, a hardness test was carried out, then continued with the heat treatment process using a temperature of 850°C for 30 minutes. The hardness test results show an increase in the hardness of S45C steel that has been coated with hard chrome, with a hardness value of S45C steel 202.70 VHN, S45C hard chrome steel 998.63 VHN. The highest hardness value is S45C steel coated with hard chrome 998.63 VHN, increasing 392.7%. Then the heat treatment process experienced a decrease in the hardness value, 528.90 VHN, with a percentage of 88.81%. The results of the microstructure observation showed that the hard chrome layer that had been heated treated showed even cracks in the hard chrome layer.

Tribological investigations had been carried out on the plasma coating (Al2O3+ ZrO2) below dry and moist abrasion stipulations according to ASTM G134. Commercial motor oil 20W40 was used as a lubricant. At a rotational speed of 200 rpm, all experiments were carried out with ordinary loads of 10, 15 and 20 Nm. Electron microscopy for scanning and AFM was used to study of the layer sprayed with paint. The outcomes of the SEM and AFM evaluation confirmed that abrasive wear is normally decided by abrasive wear in dry abrasive conditions. The lubrication and moisture check confirmed a major reduce in wear from 10 to 15 N below regular loading, and a corrosion fee larger than 15 N was once discovered below regular loading. No impact of lubrication on wear used to discovered at high loading. No impact of lubrication on wear used to be discovered at high loads. It was also cited that the plasma coating manner to improve wear resistance. The experimental statistics acquired in this study are tremendous engineering functions such as reducing equipment and internal combustion engines.

Polystyrene (PS) thin film with various concentration of mass (1%, 3%, and 5%) has been deposited onto Quartz Crystal Microbalance (QCM) surface by a spin coating method. The purpose of this research is the improvement of Bovine Serum Albumin (BSA) immobilization into the QCM surface. The QCM resonance frequency has been investigated by means of Impedance Analyzer. The film thickness was calculated by the Sauerbrey equation. The surface roughness of the PS layer was observed by noncontact Topography Measuring System (TMS-1200). Calculation result using a Sauerbrey equation shows the thickness of the PS layer increases with the increasing PS concentration. The QCM/PS with 1% and 5% concentration of mass has rougher morphology and more frequency shifts caused by BSA injection compared to 3% concentration of PS.

Pemeliharaan jalan pada perkerasan lentur dapat dilakukan dengan overlay. Overlay mengakibatkan perkerasan lentur menjadi beberapa lapisan material beraspal. Untuk melakukan overlay diberi lapisan tack coat antara lapisan lama dengan lapisan baru. Fungsi dari tack coat adalah sebagai perekat antar lapisan, selain itu juga untuk menahan gaya geser yang terjadi diantara lapis perkerasan akibat dari beban kendaraan. Penelitian ini bertujuan untuk mengetahui perilaku lekatan tack coat dengan variasi sebaran tack coat 0,25; 0,30; 0,35; dan 0,45 ltr/m² pada lapisan perkerasan jalan. Metodologi yang digunakan yaitu pengujian laboratorium dengan menggunakan alat uji geser langsung untuk menentukan kuat geser tack coat. Hasil penelitian menunjukkan nilai kuat geser meningkat sampai takaran tack coat 0,35 ltr/m², dan nilainya turun pada takaran 0,45 ltr/m². Kesimpulannya kuat geser pada lapisan perkerasan akan makin tinggi apabila jumlah takaran tack coat makin tinggi, dan kuat geser akan turun pada takaran 0,45 ltr/m².

A laminated structure of Cr-Cu coating was produced by electroplating on a carbon steel substrate. Two baths of chromium and copper electrolyte solutions were prepared to respectively deposit Cr and Cu as the first and second layer. The Cr was plated using the same plating time of 60 minutes, whereas Cu was deposit using plating time of 1 hour, 1.5 hours, 2 hours, 3 hours and 3.5 hours. The effect of plating time on the thickness, hardness and specific wear rate of the Cu surface was investigated. The formed phase, thickness, hardness and specific wear rate of the Cu surface were observed using XRD, optical microscope, Vickers microhardness tester and Ogoshi wear rate tester, respectively. The results show that Cu was formed on the surface. An increase of the Cu plating time increased the thickness and the specific wear rate of the Cu surface, but reduced the hardness of Cu surface. Cu layer was observed denser than that of Cr. This study showed that the use of Cu can be a potential candidate to laminate Cr for use in corrosive environment. Keywords